(Phys.org) —Thermometry – the measurement of temperature – is critical to a wide range of applications, including many industrial processes, biomedical monitoring, and environmental regulatory systems. However, measuring ...

(PhysOrg.com) -- For the first time, scientists have successfully operated a quantum gate between two remote particles of matter, marking an important step toward the development of a quantum computer. In previous experiments, ...

(PhysOrg.com) -- The most accurate timekeepers in the world are atomic clocks, which tell time based on the absorption of a very specific and unchanging microwave frequency, which induces electrons in an atom to “jump” ...

Physicists at the University of Sussex have tamed one of the most counterintuitive phenomena of modern science in their quest to develop a new generation of machines capable of revolutionizing the way we can solve many problems ...

A team of engineers and scientists has identified a source of electronic noise that could affect the functioning of instruments operating at very low temperatures, such as devices used in radio telescopes and advanced physics ...

(Phys.org) —SLAC scientists have found a new way to produce bright pulses of light from accelerated electrons that could shrink "light source" technology used around the world since the 1970s to examine details of atoms ...

(Phys.org) —Physicists have reproduced a pattern resembling the cosmic microwave background radiation in a laboratory simulation of the Big Bang, using ultracold cesium atoms in a vacuum chamber at the University of Chicago.

(Phys.org) —Acquired by ESA's Planck space telescope, the most detailed map ever created of the cosmic microwave background – the relic radiation from the Big Bang – was released today revealing the existence of features ...

(Phys.org)—Scientists have replaced the telescope with the microscope: Using the similarities between the structure of a crystal and the state of the cosmos in the early universe, they have explored a yet unconfirmed phenomenon, ...

Microwave

Microwaves are electromagnetic waves with wavelengths ranging from 1 m down to 1 mm, or equivalently, with frequencies between 0.3 GHz and 300 GHz.

Apparatus and techniques may be described qualitatively as "microwave" when the wavelengths of signals are roughly the same as the dimensions of the equipment, so that lumped-element circuit theory is inaccurate. As a consequence, practical microwave technique tends to move away from the discrete resistors, capacitors, and inductors used with lower frequency radio waves. Instead, distributed circuit elements and transmission-line theory are more useful methods for design and analysis. Open-wire and coaxial transmission lines give way to waveguides, and lumped-element tuned circuits are replaced by cavity resonators or resonant lines. Effects of reflection, polarization, scattering, diffraction and atmospheric absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply at all frequencies.

While the name may suggest a micrometer wavelength, it is better understood as indicating wavelengths very much smaller than those used in radio broadcasting. The boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study. The term microwave generally refers to "alternating current signals with frequencies between 0.3 GHz (3×108 Hz) and 300 GHz (3×1011 Hz)." Both IEC standard 60050 and IEEE standard 100 define "microwave" frequencies starting at 1 GHz (30 cm wavelength).

Electromagnetic waves longer (lower frequency) than microwaves are called "radio waves". Electromagnetic radiation with shorter wavelengths may be called "millimeter waves", terahertz radiation or even T-rays. Definitions differ for millimeter wave band, which the IEEE defines as 110 GHz to 300 GHz.